/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <sys/zfs_context.h>

#include <sys/spa.h>

#include <sys/vdev_file.h>

#include <sys/vdev_impl.h>

#include <sys/zio.h>

#include <sys/fs/zfs.h>

/*

 * Virtual device vector for files.

 */

static int

vdev_file_open_common(vdev_t *vd)

{

	vdev_file_t *vf;

	vnode_t *vp;

	int error;

	/*

	 * We must have a pathname, and it must be absolute.

	 */

	if (vd->vdev_path == NULL || vd->vdev_path[0] != '/') {

		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;

		return (EINVAL);

	}

	vf = vd->vdev_tsd = kmem_zalloc(sizeof (vdev_file_t), KM_SLEEP);

	/*

	 * We always open the files from the root of the global zone, even if

	 * we're in a local zone.  If the user has gotten to this point, the

	 * administrator has already decided that the pool should be available

	 * to local zone users, so the underlying devices should be as well.

	 */

	ASSERT(vd->vdev_path != NULL && vd->vdev_path[0] == '/');

	error = vn_openat(vd->vdev_path + 1, UIO_SYSSPACE,

	    spa_mode | FOFFMAX, 0, &vp, 0, 0, rootdir, -1);

	if (error) {

		vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;

		return (error);

	}

	vf->vf_vnode = vp;

#ifdef _KERNEL

	/*

	 * Make sure it's a regular file.

	 */

	if (vp->v_type != VREG) {

		vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;

		return (ENODEV);

	}

#endif

	return (0);

}

static int

vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)

{

	vdev_file_t *vf;

	vattr_t vattr;

	int error;

	if ((error = vdev_file_open_common(vd)) != 0)

		return (error);

	vf = vd->vdev_tsd;

	/*

	 * Determine the physical size of the file.

	 */

	vattr.va_mask = AT_SIZE;

	error = VOP_GETATTR(vf->vf_vnode, &vattr, 0, kcred, NULL);

	if (error) {

		vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;

		return (error);

	}

	*psize = vattr.va_size;

	*ashift = SPA_MINBLOCKSHIFT;

	return (0);

}

static void

vdev_file_close(vdev_t *vd)

{

	vdev_file_t *vf = vd->vdev_tsd;

	if (vf == NULL)

		return;

	if (vf->vf_vnode != NULL) {

		(void) VOP_PUTPAGE(vf->vf_vnode, 0, 0, B_INVAL, kcred, NULL);

		(void) VOP_CLOSE(vf->vf_vnode, spa_mode, 1, 0, kcred, NULL);

		VN_RELE(vf->vf_vnode);

	}

	kmem_free(vf, sizeof (vdev_file_t));

	vd->vdev_tsd = NULL;

}

static int

vdev_file_probe_io(vdev_t *vd, caddr_t data, size_t size, uint64_t offset,

    enum uio_rw rw)

{

	vdev_file_t *vf = vd->vdev_tsd;

	ssize_t resid;

	int error = 0;

	if (vd == NULL || vf == NULL || vf->vf_vnode == NULL)

		return (EINVAL);

	ASSERT(rw == UIO_READ || rw ==  UIO_WRITE);

	error = vn_rdwr(rw, vf->vf_vnode, data, size, offset, UIO_SYSSPACE,

	    0, RLIM64_INFINITY, kcred, &resid);

	if (error || resid != 0)

		return (EIO);

	return (0);

}

static int

vdev_file_probe(vdev_t *vd)

{

	vdev_t *nvd;

	char *vl_boot;

	uint64_t offset;

	int l, error = 0, retries = 0;

	if (vd == NULL)

		return (EINVAL);

	/* Hijack the current vdev */

	nvd = vd;

	/*

	 * Pick a random label to rewrite.

	 */

	l = spa_get_random(VDEV_LABELS);

	ASSERT(l < VDEV_LABELS);

	offset = vdev_label_offset(vd->vdev_psize, l,

	    offsetof(vdev_label_t, vl_boot_header));

	vl_boot = kmem_alloc(VDEV_BOOT_HEADER_SIZE, KM_SLEEP);

	while ((error = vdev_file_probe_io(nvd, vl_boot, VDEV_BOOT_HEADER_SIZE,

	    offset, UIO_READ)) != 0 && retries == 0) {

		/*

		 * If we failed with the vdev that was passed in then

		 * try allocating a new one and try again.

		 */

		nvd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);

		if (vd->vdev_path)

			nvd->vdev_path = spa_strdup(vd->vdev_path);

		error = vdev_file_open_common(nvd);

			break;

	}

	if ((spa_mode & FWRITE) && !error) {

		error = vdev_file_probe_io(nvd, vl_boot, VDEV_BOOT_HEADER_SIZE,

		    offset, UIO_WRITE);

	}

	if (retries) {

		vdev_file_close(nvd);

		if (nvd->vdev_path)

			spa_strfree(nvd->vdev_path);

		kmem_free(nvd, sizeof (vdev_t));

	}

	kmem_free(vl_boot, VDEV_BOOT_HEADER_SIZE);

	if (!error)

		vd->vdev_is_failing = B_FALSE;

	return (error);

}

static void

vdev_file_io_start(zio_t *zio)

{

	vdev_t *vd = zio->io_vd;

	vdev_file_t *vf = vd->vdev_tsd;

	ssize_t resid;

	int error;

	if (zio->io_type == ZIO_TYPE_IOCTL) {

		zio_vdev_io_bypass(zio);

		/* XXPOLICY */

		if (!vdev_readable(vd)) {

			zio->io_error = ENXIO;

			zio_next_stage_async(zio);

			return;

		}

		switch (zio->io_cmd) {

		case DKIOCFLUSHWRITECACHE:

			zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,

			    kcred, NULL);

			dprintf("fsync(%s) = %d\n", vdev_description(vd),

			    zio->io_error);

			break;

		default:

			zio->io_error = ENOTSUP;

		}

		zio_next_stage_async(zio);

		return;

	}

	/*

	 * In the kernel, don't bother double-caching, but in userland,

	 * we want to test the vdev_cache code.

	 */

#ifndef _KERNEL

	if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0)

		return;

#endif

	if ((zio = vdev_queue_io(zio)) == NULL)

		return;

	/* XXPOLICY */

	if (zio->io_type == ZIO_TYPE_WRITE)

		error = vdev_writeable(vd) ? vdev_error_inject(vd, zio) : ENXIO;

	else

		error = vdev_readable(vd) ? vdev_error_inject(vd, zio) : ENXIO;

	error = (vd->vdev_remove_wanted || vd->vdev_is_failing) ? ENXIO : error;

	if (error) {

		zio->io_error = error;

		zio_next_stage_async(zio);

		return;

	}

	zio->io_error = vn_rdwr(zio->io_type == ZIO_TYPE_READ ?

	    UIO_READ : UIO_WRITE, vf->vf_vnode, zio->io_data,

	    zio->io_size, zio->io_offset, UIO_SYSSPACE,

	    0, RLIM64_INFINITY, kcred, &resid);

	if (resid != 0 && zio->io_error == 0)

		zio->io_error = ENOSPC;

	zio_next_stage_async(zio);

}

static void

vdev_file_io_done(zio_t *zio)

{

	if (zio_injection_enabled && zio->io_error == 0)

		zio->io_error = zio_handle_device_injection(zio->io_vd, EIO);

	/*

	 */

	if (zio->io_error == EIO) {

		vdev_t *vd = zio->io_vd;

		if (vdev_probe(vd) != 0)

			vd->vdev_is_failing = B_TRUE;

	}

	vdev_queue_io_done(zio);

#ifndef _KERNEL

	if (zio->io_type == ZIO_TYPE_WRITE)

		vdev_cache_write(zio);

#endif

	zio_next_stage(zio);

}

vdev_ops_t vdev_file_ops = {

	vdev_file_open,

	vdev_file_close,

	vdev_file_probe,

	vdev_default_asize,

	vdev_file_io_start,

	vdev_file_io_done,

	NULL,

	VDEV_TYPE_FILE,		/* name of this vdev type */

	B_TRUE			/* leaf vdev */

};

/*

 * From userland we access disks just like files.

 */

#ifndef _KERNEL

vdev_ops_t vdev_disk_ops = {

	vdev_file_open,

	vdev_file_close,

	vdev_file_probe,

	vdev_default_asize,

	vdev_file_io_start,

	vdev_file_io_done,

	NULL,

	VDEV_TYPE_DISK,		/* name of this vdev type */

	B_TRUE			/* leaf vdev */

};

#endif